High polarizability enhanced EPR, Optical linear& nonlinear and electric conductivity: role of NiFe2O4 nanocrystals in transparent tellurite glass-ceramics

Glass containing magnetic nanocrystals is attractive to obtain high nonlinear and high polarizability. In this study, for the first time, 10 nm cubic NiFe2O4 (NFO) nanocrystals doped tellurite glass was studied in terms of the influence on glass structure, chemical bonds, EPR spectra, optical linear and nonlinearity, complex impedance, and dielectric constant. X-ray diffraction, FT-IR, and X-ray photoelectron spectroscopy revealed the single phase and chemical energy of NFO NCs and NFO-doped glasses. The introduction of NFO modified the glass structure through conversion of TeO4 -> TeO3, and PO4 -> PO3 units and producing non -bridging oxygen, which in turn enhanced the polarizability according. EPR analysis revealed the super -exchange interaction between multi-valence states of Ni and Fe ions, contributing to the deformation of NFO lattice and NBO defects in the glass network. The energy band gap of glass was red-shifted by NFO due to the multi-valence states of 3d ions. In addition, the linear and nonlinear refractive index, third-order absorption coefficient, and susceptibility were significantly enhanced because of the high polarizability. 3% NFO glass demonstrated huge third-order nonlinear susceptibility of 9.37 x 10-7 esu and giant DC electric conductivity of 8.84 x 10-4 S/cm at room temperature. The values obtained in the present study were much superior to values from the literature, and the obtained glasses are promising for high ultra-fast laser, supercontinuum generation, and holography applications. (c) 2022 Elsevier B.V. All rights reserved.